Economic constraints have led railway companies to develop portable units allowing a ground based operator to remotely control a locomotive is a switching yard. The unit is essentially a transmitter communicating with a slave controller on the locomotive by way of a radio link. Typically, the operator carries this unit and can perform duties such as coupling and uncoupling cars while remaining in control of the locomotive movement at all times. This allows for placing the point of control at the point of movement thereby potentially enhancing safety, accuracy and efficiency.
Remote locomotive controllers currently used in the industry are relatively simple devices that enable the operator to manually regulate the throttle and brake in order to accelerate, decelerate and/or maintain a desired speed. The operator is required to judge the speed of the locomotive and modulate the throttle and/or brake levers to control the movement of the locomotive. Therefore, the operator must possess a good understanding of the track dynamics, the braking characteristics of the train, etc. in order to remotely operate the locomotive in a safe manner.